The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Warren E Dixon - One of the best experts on this subject based on the ideXlab platform.
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tracking control of limit cycle oscillations in an aero elastic system
Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 2014Co-Authors: B J Bialy, Crystal L Pasiliao, Huyen Dinh, Warren E DixonAbstract:Limit cycle oscillations (LCOs) affect current fighter aircraft and are expected to be present on next generation fighter aircraft. Current efforts in control systems designed to suppress LCO behavior have either used a linear model, restricting the flight regime, require exact knowledge of the system dynamics, or require uncertainties in the system dynamics to be linear-in-the-parameters and only present in the torsional stiffness. Furthermore, the aerodynamic model used in prior research efforts neglects nonlinear effects. This paper presents the development of a controller consisting of a continuous robust integral of the sign of the error (RISE) Feedback Term with a neural network (NN) feedforward Term to achieve asymptotic tracking of uncertainties that do not satisfy the linear-in-the-parameters assumption. Simulation results are presented to validate the performance of the developed controller.
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closed loop neural network based nmes control for human limb tracking
IEEE Transactions on Control Systems and Technology, 2012Co-Authors: Nitin Sharma, C M Gregory, M Johnson, Warren E DixonAbstract:Closed-loop control of skeletal muscle is complicated by the nonlinear muscle force to length and velocity relationships and the inherent unstructured and time-varying uncertainties in available models. Some pure Feedback methods have been developed with some success, but the most promising and popular control methods for neuromuscular electrical stimulation (NMES) are neural network (NN)-based methods. Efforts in this paper focus on the use of a NN feedforward controller that is augmented with a continuous robust Feedback Term to yield an asymptotic result (in lieu of typical uniformly ultimately bounded stability). Specifically, an NN-based controller and Lyapunov-based stability analysis are provided to enable semi-global asymptotic tracking of a desired limb time-varying trajectory (i.e., non-isometric contractions). The developed controller is applied as an amplitude modulated voltage to external electrodes attached to the distal-medial and proximal-lateral portion of the quadriceps femoris muscle group in non-impaired volunteers. The added value of incorporating a NN feedforward Term is illustrated through experiments that compare the developed controller with and without the NN feedforward component.
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global adaptive output Feedback tracking control of robot manipulators
IEEE Transactions on Automatic Control, 2000Co-Authors: F Zhang, D M Dawson, M S De Queiroz, Warren E DixonAbstract:This paper presents a solution to the problem of global, output Feedback, tracking control of uncertain robot manipulators, specifically, a desired compensation adaptation law plus a nonlinear Feedback Term coupled to a dynamic nonlinear filter is designed to produce global asymptotic link position tracking while compensating for parametric uncertainty and requiring only link position measurements.
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global adaptive output Feedback tracking control of robot manipulators
Conference on Decision and Control, 1997Co-Authors: F Zhang, D M Dawson, M S De Queiroz, Warren E DixonAbstract:This paper presents a solution to the problem of global, output Feedback tracking control of uncertain robot manipulators. Specifically, a desired compensation adaptation law plus a nonlinear Feedback Term coupled to a dynamic nonlinear filter is designed to produce global asymptotic link position tracking errors while compensating for parametric uncertainty and requiring only link position measurements. Simulation results are provided to illustrate the controller performance.
Gong-you Tang - One of the best experts on this subject based on the ideXlab platform.
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Optimal rejection with zero steady-state error to disturbances for a class of nonlinear systems with time-delay
Proceedings of the 29th Chinese Control Conference, 2010Co-Authors: Xixin Yang, Gong-you TangAbstract:The optimal disturbance rejection problem with zero steady-state error for a class of nonlinear systems with time-delay is considered. Based on the internal model principle, a disturbance compensator is designed to remove the influence of external disturbance. By using the maximum principle, the optimal control problem is constructed to solve the nonlinear two-point boundary value problem with both time-delay and time-advanced Terms. The successive approximation approach is used to obtain the decoupling form of the optimal compensator and the optimal Feedback Term. Simulation results demonstrate the effectiveness of the optimal disturbance rejection control law.
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Optimal Disturbance Rejection with Zero Steady-State Error for Time-Delay Systems
2006 6th World Congress on Intelligent Control and Automation, 2006Co-Authors: Hong-wei Gao, Gong-you TangAbstract:We consider an optimal disturbance rejection problem for time-delay systems with persistent disturbances. In order to realize disturbance rejection with zero steady-state error, a disturbance compensator is constructed based on the internal model principle. At the same time, the optimal disturbance rejection problem with zero steady-state error is transformed into an optimal control problem for time-delay systems without disturbances. Then by introducing a sensitivity parameter, the original problem is reduced to solving a series of two-point boundary value (TPBV) problems without delay or advance Terms. The obtained optimal control law consists of an analytic state Feedback Term and a compensation Term, which is a series sum of the adjoint vectors. By truncating a finite Terms of the adjoint vectors series, we obtain a suboptimal Feedback control law with zero steady-state error. A simulation example shows the effectiveness of the presented algorithm.
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suboptimal control for nonlinear systems a successive approximation approach
Systems & Control Letters, 2005Co-Authors: Gong-you TangAbstract:Abstract This paper presents a successive approximation approach (SAA) designing optimal controllers for a class of nonlinear systems with a quadratic performance index. By using the SAA, the nonlinear optimal control problem is transformed into a sequence of nonhomogeneous linear two-point boundary value (TPBV) problems. The optimal control law obtained consists of an accurate linear Feedback Term and a nonlinear compensation Term which is the limit of an adjoint vector sequence. By using the finite-step iteration of the nonlinear compensation sequence, we can obtain a suboptimal control law. Simulation examples are employed to test the validity of the SAA.
Guanrong Chen - One of the best experts on this subject based on the ideXlab platform.
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a connectivity preserving flocking algorithm for multi agent dynamical systems with bounded potential function
Iet Control Theory and Applications, 2012Co-Authors: Guanghui Wen, Zhisheng Duan, Guanrong ChenAbstract:Without assuming that the communication topology can remain its connectivity frequently enough and the potential function can provide an infinite force during the evolution of agents, the flocking problem of multi-agent systems with second-order non-linear dynamics is investigated in this study. By combining the ideas of collective potential functions and velocity consensus, a connectivity-preserving flocking algorithm with bounded potential function is proposed. Using tools from the algebraic graph theory and matrix analysis, it is proved that the designed algorithm can guarantee the group of multiple agents to asymptotically move with the same velocity while preserving the network connectivity if the coupling strength of the velocity consensus Term is larger than a threshold value. Furthermore, the flocking algorithm is extended to solve the flocking problem of multi-agent systems with a dynamical virtual leader by adding a navigation Feedback Term. In this case, each informed agent only has partial velocity information about the leader, yet the present algorithm not only can guarantee the velocity of the whole group to track that of the leader asymptotically, and also can preserve the network connectivity. Finally, some numerical simulations are provided to illustrate the theoretical results.
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a connectivity preserving flocking algorithm for nonlinear multi agent systems with bounded potential function
Chinese Control Conference, 2011Co-Authors: Guanghui Wen, Zhisheng Duan, Guanrong ChenAbstract:Without assuming that the communication topology can maintain its connectivity frequently enough during the evolution of agents, the flocking problem of multi-agent systems with second-order nonlinear dynamics is investigated in this paper. By combining the ideas of collective potential functions and velocity consensus, a connectivity-preserving flocking algorithm with bounded potential function is proposed. Using tools from algebraic graph theory and matrix analysis, it is shown that the present algorithm can enable the group of multiple agents to move with the same velocity while preserving the connectivity of the whole network if the the algebraic connectivity of the initial network is larger than a threshold value. Furthermore, the flocking algorithm is used to solve the flocking problem of multi-agent systems with a virtual leader by adding a navigation Feedback Term. In this case, each informed agent only has partial velocity information about the leader, yet the present algorithm not only can guarantee the velocity of the whole group to track that of the leader asymptotically, and also can preserve the connectivity of the network. Finally, simulation results are provided to valid the effectiveness of the theoretical results.
Guanghui Wen - One of the best experts on this subject based on the ideXlab platform.
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a connectivity preserving flocking algorithm for multi agent dynamical systems with bounded potential function
Iet Control Theory and Applications, 2012Co-Authors: Guanghui Wen, Zhisheng Duan, Guanrong ChenAbstract:Without assuming that the communication topology can remain its connectivity frequently enough and the potential function can provide an infinite force during the evolution of agents, the flocking problem of multi-agent systems with second-order non-linear dynamics is investigated in this study. By combining the ideas of collective potential functions and velocity consensus, a connectivity-preserving flocking algorithm with bounded potential function is proposed. Using tools from the algebraic graph theory and matrix analysis, it is proved that the designed algorithm can guarantee the group of multiple agents to asymptotically move with the same velocity while preserving the network connectivity if the coupling strength of the velocity consensus Term is larger than a threshold value. Furthermore, the flocking algorithm is extended to solve the flocking problem of multi-agent systems with a dynamical virtual leader by adding a navigation Feedback Term. In this case, each informed agent only has partial velocity information about the leader, yet the present algorithm not only can guarantee the velocity of the whole group to track that of the leader asymptotically, and also can preserve the network connectivity. Finally, some numerical simulations are provided to illustrate the theoretical results.
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a connectivity preserving flocking algorithm for nonlinear multi agent systems with bounded potential function
Chinese Control Conference, 2011Co-Authors: Guanghui Wen, Zhisheng Duan, Guanrong ChenAbstract:Without assuming that the communication topology can maintain its connectivity frequently enough during the evolution of agents, the flocking problem of multi-agent systems with second-order nonlinear dynamics is investigated in this paper. By combining the ideas of collective potential functions and velocity consensus, a connectivity-preserving flocking algorithm with bounded potential function is proposed. Using tools from algebraic graph theory and matrix analysis, it is shown that the present algorithm can enable the group of multiple agents to move with the same velocity while preserving the connectivity of the whole network if the the algebraic connectivity of the initial network is larger than a threshold value. Furthermore, the flocking algorithm is used to solve the flocking problem of multi-agent systems with a virtual leader by adding a navigation Feedback Term. In this case, each informed agent only has partial velocity information about the leader, yet the present algorithm not only can guarantee the velocity of the whole group to track that of the leader asymptotically, and also can preserve the connectivity of the network. Finally, simulation results are provided to valid the effectiveness of the theoretical results.
F Zhang - One of the best experts on this subject based on the ideXlab platform.
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global adaptive output Feedback tracking control of robot manipulators
IEEE Transactions on Automatic Control, 2000Co-Authors: F Zhang, D M Dawson, M S De Queiroz, Warren E DixonAbstract:This paper presents a solution to the problem of global, output Feedback, tracking control of uncertain robot manipulators, specifically, a desired compensation adaptation law plus a nonlinear Feedback Term coupled to a dynamic nonlinear filter is designed to produce global asymptotic link position tracking while compensating for parametric uncertainty and requiring only link position measurements.
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global adaptive output Feedback tracking control of robot manipulators
Conference on Decision and Control, 1997Co-Authors: F Zhang, D M Dawson, M S De Queiroz, Warren E DixonAbstract:This paper presents a solution to the problem of global, output Feedback tracking control of uncertain robot manipulators. Specifically, a desired compensation adaptation law plus a nonlinear Feedback Term coupled to a dynamic nonlinear filter is designed to produce global asymptotic link position tracking errors while compensating for parametric uncertainty and requiring only link position measurements. Simulation results are provided to illustrate the controller performance.
